1. Field of the Invention
The present invention relates to a cleaning method of coloring device of optical fiber, and a coloring device of optical fiber.
2. Description of the Related Art
A resin coating of an optical fiber is colored in different colors among optical fibers to identify each of the optical fibers. Coloring of optical fibers is performed by passing them through a coloring device. Generally, optical fibers are colored by using one coloring device, even though they are supposed to be coated in different colors. After a certain optical fiber is coated with a certain color, the coloring device is cleaned to wash out the ink, the ink of another color is supplied to the device, and another optical fiber is colored. By cleaning the coloring device like this, mixing of inks of different colors is prevented, thereby achieving a coating of a desired color.
Meanwhile, there has been disclosed a resin coating device that forms a high-quality resin coating in a state of having a drawing speed set high in a process of forming a resin coating on an optical fiber. The resin coating device includes a nipple, a first die, and a second die to sequentially pass optical fibers therethrough. A resin pool is formed at an external periphery of the nipple, and resin path is formed between the nipple and the first and the second dies. An optical fiber passing hole of the second die has a tapered part having an internal diameter of the hole reduced toward a passing direction of the optical fiber. According to this resin coating device, when a resin is supplied to the resin pool from outside, the resin is supplied to an external periphery of an optical fiber through the resin path and is coated onto the optical fiber. In this case, because the optical fiber passing hole of the second die has the tapered part, the resin can be coated stably. Such a structure of the resin coating device is also considered to be effective in performing high-quality coloring in a state where a passage speed of the optical fiber is set high in the coloring device.